[CI][OSSF]Set permissions on sycl-issues-ping-assignee (#14272)

Set read-all permissions on this workflow as it should not require any
write permissions

Author: stdale-intel

.github/workflows/sycl-issues-ping-assignee.yml

@@ -14,6 +14,8 @@ on:
   schedule:
     - cron: '0 0 * * *'
 
+permissions: read-all
+
 jobs:
   run:
     runs-on: ubuntu-20.04